1. Field of the Invention
The present invention relates generally to printing presses and more particularly to a device and method for transporting printed products.
2. Background Information
Web printing presses print a continuous web of material, such as paper. The continuous web then is cut in a cutting unit so as to form book blocks. These book blocks can be sections of a newspaper, for example. In order to transport or process the book blocks, for example to perform a triming operation, it is often desirable to firmly grip the book in a book clamp which is moveable along a track.
U.S. Pat. No. 3,702,129 purports to describe a mechanical book clamp which can accommodate various book thicknesses. A chain drive can be used to move individual clamps along a desired path. The books are gripped from above between an inner clamp plate and a pivotal outer book plate, which is actuated by an actuating means.
The device of this patent has the disadvantage that the book clamps require a complicated actuating mechanism and that entire book clamp is fixed to the chain drive. Thus, if the book is to be transferred to a path different from the chain drive path, the signature must be fully released and transferred to a separate device. During this transfer, the book block can be damaged. For example, dog-earring may occur during such transfers.
An object of the present invention is to provide for a device and method for gripping and transporting printed products whereby damage to the printed products. may be reduced. An additional or alternative object of the present invention is to provide for adequate gripping of the printed products.
The present invention provides a device for transporting printed products including a plurality of individual pocket grippers, each pocket gripper having a first connector on one side and a second connector on a second side, and having gripping elements for gripping a printed product. These gripping elements may include a front plate and a rear plate, with the printed product gripped between the front and rear plate. A plurality of transport units is also provided, with each transport unit being movable along a track and being releasably attached to the first connector of a respective one of the plurality of pocket grippers.
The connectors of the pocket grippers are preferably bars, one of which is gripped by the transport unit, so that the pocket grippers may be moved along a track. The transport unit thus preferably has a jaw set for firmly grasping one of the bars.
As the products are to be transmitted along the track, the second connector is free and not grasped by a transport unit. When the products are to be changed to a different track, the second connector can be grasped by transport units traveling along the second track. The first connector is then released, and then the product travel along the second track. Thus the product does not need to be re-gripped upon a path change, thus eliminating or reducing the potential for damage to the product.
Moreover, the product may remain gripped in the pocket grippers while passing through various work stations, which also reduces the need for re-gripping of products. The fact that the product is firmly gripped between two plates also helps prevent fluff from entering between sheets of the product. Moreover, the use of the pocket grippers permits a same transfer point on the pocket grippers to be used to transfer the products, independent of product size or shape. This same grip point provides versatility in transport of products, in that both big phone books or small leaflets can have the same transfer point on a pocket gripper, for example.
The present invention also provides a method for transporting printed products including the steps of gripping a printed product in a gripper pocket, moving the gripper pocket along a track, and releasing the gripper pocket while the printed product remains gripped.
The method further includes grasping the released gripper pocket and moving the released gripper pocket along a second track.